We herein describe the case of a 59-year-old Japanese man with diabetes mellitus who presented with vertebral osteomyelitis caused by Salmonella enterica subspecies enterica serovar Enteritidis. The patient presented with a persistent fever without back pain. Extraintestinal infections of Salmonella species are well known and are often reported in immunocompromised patients; however, they are rare in non-immunosuppressed patients. The protracted course and atypical presentation of osteomyelitis in diabetic adults can lead to major diagnostic delays. Moreover, in recent years, decreased fluoroquinolone susceptibility against salmonellosis has become a problem worldwide, a problem that needs to be urgently addressed.